Thank you John: I just got back from a morning's flying in a local gym using the subject plane. It is built to Pennyplane specs at 3.1 grams, and I did not see any restrictions on the prop diameter. I didn't design to the LPP rules. Also I am not interested in competition at this point, being absoultely enthralled with just watching it in the air!
I was winding up to 0.7 oz-in, but without the "unwinding" part. I will try that next time... Today, I was still around the three minute mark.
To get a steeper climb to obtain more loading on the prop, I imagine I should go more positive on the thrust angle, for the glide is on the ragged edge of a stall already. Do you have an opinion, or suggestion on getting to that steeper climp?
Thanks, Richard
--- In Indoor_Construction_at_yahoogroups.com, "John Barker" <john.barker783@...> wrote:
>
> Richard
>
> I am not an Indoor expert but I have flown an LPP under a ceiling similar to yours so the following may be of some use.
>
> We fly our LPP competitions with 0.75g of rubber and a 0.75g spacer. I have notes of using motors of 0.054 and 0.056 g/inch which will be a strip width of just over 0.08" as compared to your 3/32 (0.094"). Best flights were wound to about 1 inch.oz of torque (about 850 turns) and backed off to a launch torque of 0.7 inch.oz. The only 'turns left' figure I recorded was 45. Best flights were about 4.5 minutes.
>
> Your aeroplane looks very good and well made but I recommend that you have a check on the propeller dimensions. My propeller is 12" diameter with a blade angle of 40 degrees at the three quarter radius. This gives a nominal P/D ratio of 1.98.
>
> Your model is certainly flying very smoothly but to my, not very expert, eye too smoothly for a low ceiling. My model flies the early circuits much nearer the stall, nose well up, flying very slowly and thus stalling the propeller and reducing rpm and not climbing very much. As the torque reduces the nose drops and the climb rate increases.
>
> Don't take my figures as 'best practice' but they are at least something to compare to your own.
>
> John
>
Received on Thu May 24 2012 - 14:59:09 CEST
This archive was generated by Yannick on Sat Dec 14 2019 - 19:13:47 CET